Part 1 – Diagnosis
Most of us adopt an intelligent approach to exercise. We engage in it, recognizing the impact fitness has on our overall health. We go to the gym and play sports. But do we really understand the science of aging muscles?
Recently, an article in The New York Times (Gretchen Reynolds1, March 23, 2017: The best exercise for aging muscles) came to my attention and it throws some fascinating new light on an issue I would guess is misunderstood by most of us.
Mitochondria and cell metabolism
Writes Ms. Reynolds: ‘The toll that aging takes on a body extends all the way down to the cellular level. But the damage accrued by cells in older muscles is especially severe, because they do not regenerate easily and they become weaker as their mitochondria, which produce energy, diminish in vigor and number.’
The Mayo Clinic recently performed a research exercise on the cells of 72 healthy but sedentary men and women who were younger or older than 64. Baseline measures were established covering their aerobic fitness, blood-sugar levels and the mitochondrial health in their muscle cells. Then they were assigned to a variable exercise regime.
The exercise regime
- One segment performed vigorous weight training several times a week.
- Another segment did brief interval training three times a week on stationary bicycles, pedaling hard for four minutes, resting for three and then repeating that sequence three more times.
- A third segment rode stationary bikes at a moderate pace for 30 minutes a few times a week and lifted weights lightly on other days.
- A fourth segment, the control, did not exercise.
Results: it’s all about interval training and intensity 2
- Everyone who exercised became fitter. No surprise here. Those exercising with weights gained muscle mass. Those who engaged in interval training gained endurance. Hardly surprising, on either count.
- Then the researchers biopsied the muscle cells. Among the younger subjects who went through interval training, the activity levels had changed in 274 genes, compared with 170 genes for those who exercised more moderately and 74 for the weight lifters.
- Among the older group engaged in interval training, almost 400 genes were working differently now, compared with 33 for the weight lifters and only 19 for the moderate exercisers.
Interval training influences the ability of mitochondria to produce energy for muscle cells.
Those who did the interval workouts showed increases in the number and health of their mitochondria — an impact that was particularly pronounced among the older cyclists.
Decline in the cellular health of muscles associated with aging was ‘corrected’ with exercise, especially if it was intense.
Older people’s cells responded in some ways more robustly to intense exercise than the cells of the young did.
It is never too late – you can never be too old, in other words – to benefit from exercise, the more intense the better.
Tune in to my follow-up blog, which describes a specific exercise routine for aging muscles, to be posted soon.
Dave Ritcey, The Ritcey Team, Scotia Wealth Management
Global markets have started 2018 in solid fashion with healthy performances across equities (S&P500 +3.1%; S&P/TSX +0.9%), commodities (WTI crude oil +4.1%, gold +0.9%) and currencies (CAD +1.0%) in the first week of trading. Bond yields are also on the march higher year-to-date with U.S. and Canada 10-year federal government bond yields up by 15bp to 2.54% and 2.19%, respectively. These early gains can be attributed to, among other things, ongoing solid economic growth data and the recently approved U.S. tax cut package in late December, which boosts the corporate profit outlook, in our view.